1. Field of the Invention
The present invention relates to a soldering tool and in particular, to a gas powered soldering tool, in which the soldering tip is heated by a gas catalytic combustion element. It also relates to a portable soldering tool. Further, it relates to a heating device for a gas powered heating apparatus, and also to the heating apparatus incorporating the heating device.
2. Discussion of the Prior Art
Gas powered soldering tools are known. One such device is disclosed in U.S. Pat. No. 4133301. This device comprises a soldering tip, a gas reservoir and means for selectively delivering gas from the reservoir to the soldering tip. The soldering tip comprises a soldering portion and a cylindrical member extending rearwardly from the soldering portion. The cylindrical member is packed with a permeable gas catalytic combustion element, and gas is delivered from a jet to the combustion element at the end remote from the soldering portion. The combustion element heats up and in turn heats the cylindrical member.
Heat is conducted along the cylindrical member into the soldering portion. However, this device like most other known devices, suffers from two major problems. Firstly, by virtue of the fact that heat is transferred from the combustion element to the soldering portion along the cylindrical member, only a limited amount of the heat generated in the combustion element is actually conducted to the soldering portion. Because the cylindrical member is effectively an outer shell, a considerable quantity of the heat on the shell is convected away by the surrounding air. Thus heat is thus lost to the soldering portion. A second problem with this device is that by virtue of the fact that the gas is delivered to the combustion element at one end only, even distribution of the gas throughout the combustion element is unachievable. In general, what happens in these devices is that the end of the catalytic combustion element remote from the soldering portion burns brightly and hotly, while the end adjacent the soldering portion in many cases can be quite cool. This, it will be appreciated, is a considerable disadvantage in that to obtain optimum combustion efficiency from the combustion element, it is essential that the gas should burn evenly throughout. While one of the devices described in U.S. Pat. No. 4,133,301 does attempt to deliver the gas more evenly throughout the combustion element, this device does not overcome the problem of a considerable amount of heat in the cylindrical member being lost to the surrounding air.
Thus, in use, this device and other known devices tend to be relatively inefficient in use, in that the gas is unevenly burnt in the catalytic combustion element, and secondly, because of the high heat loss from the cylindrical member, both a large quantity of fuel is required to heat the tip and also a large catalytic combustion element is also required. This further leads to a relatively bulky and cumbersome apparatus.